The Dragonfly Phenomenon

I don't know what is with all the dragonflies this year but they are crazy! Last night when I was sitting in report at work, I looked out the window and there were just hundreds of them darting around. When one of my friends came back from her break she said her husband had taken a picture of all the dragonflies in there front yard. I guess they were just solid out there. I don't know what has caused such an increase in them but these "miniature helicopters" are beautiful and they eat mosquitoes so I'm all for that.